ampage Tube Amps / Music Electronics	For current discussions, please visit Music Electronics Forum.

ampage archive

Vintage threads from the first ten years

Re: Silver plated copper wire

4/26/2000 5:10 AM
Mark L.	Re: Silver plated copper wire In the previous post, I meant to say that "in the world of Metals, Silver is the best HEAT conducting metal, on the Planet..." Silver is also the best electrical conductor, too. In these 2 categories, Silver is KING of all the Metals.... Mark L.

4/26/2000 2:54 PM
MBSetzer	Mark L. Wrote: >Silver is the best conductor of heat on the Planet, this molten >blob will certainly Stay hot and liquid longer than one is normally >used to. An interesting thing about heat-conducting materials (hmm . . . wouldn't that be all materials?) is that the better the conduction, the more rapidly the same mass will cool off from the same temperature when exposed to the same environment. In other words, as you observe the molten blob of silver-bearing solder stay hot & liquid longer than you are used to, it would NOT be due to superior heat conduction because of its silver content. Just the contrary, if you would heat ordinary 60/40 solder beyond its melting point to the same temperature that the higher-melting silver-bearing solder requires, it would take even longer to cool down to room temperature than the silver stuff. Now lets dissolve another misconception. >The temperature of easy flow solder(even Silver bearing solder) is >just not high enough to turn anything Silver into a liquid state. >Even a thin micron-thick veneer like a plating. Soldering irons don't >get hot enough to turn Silver into liquid form. This takes a torch(or >equivalent) to do. Since silver has long been known to dissolve in solder, it would naturally raise questions about any observations to the contrary. A common occurrence in the scientific laboratory is preliminary observation that needs further investigation, especially in those situations where the outcome may be unknown Therefore the following experiment is suggested: Of course you will need some pure silver (20 ga. wire would be about right), but who has that kind of stuff just lying around A clipping from the wire about 1 or 2 millimeters long would be a good test piece. Also you would need a different metal for a control sample, something known to be insoluble in solder, like stainless steel, in about the same size & shape as the silver. Probably a hardened sewing needle could be trimmed to size. All proper laboratory safety equipment, especially eye protection when using clippers to trim metal stock, should be employed. It might be nice to use a small ceramic crucible for the melted solder, but it could be better done on a level piece of wood (the amount of heat will not scorch it that bad), since the molten solder will have the consistency of ordinary liquid mercury and kind of hold the blob together, you don't want it to run downhill though. For a heat source an ordinary soldering iron like they have at Radio Shack would be OK. Since you will be melting a blob of solder about 1 centimeter in diameter which is much bigger than most amplifier connections, use about a 50W iron instead of a 25W. Start with the stainless piece and get a blob of solder hot nearby, use a little more than would stick to the tip of the iron when you lift it from the work area. Push the liquid solder to engulf the stainless test piece and seriously try to agitiate and heat the stainless together with the solder and get it to dissolve. Notice how even if the solder slightly wets the insoluble metal, you can always separate it from the liquid by dragging the blob and leaving the test piece behind. Now repeat using the silver test piece, when it becomes difficult to leave any solid silver behind when moving the blob, record your impression of what has become of the silver at this point. If there is some suspicion that solid silver is suspended within the liquid solder without being dissolved, this could be confirmed or denied by passing the liquid through a stainless mesh with openings small enough to catch the original size test piece. Or you might use an intact sewing needle to probe around in the melted solder to see if any solid silver is still there. Don't hold the needle with your bare hands for this. ----- Review your impressions and comment on whether you think the temperature reached by the easy flow solder using an ordinary soldering iron was high enough to turn any silver into the liquid state. ----- Would you say that smaller amounts of silver, such as a thin micron-thick veneer-like plating would dissolve faster or slower than your experimental test piece? ----- Could you qualify the statement: Soldering irons don't get hot enough to turn silver into liquid form? Do you think it is surprising for pure metals with higher melting points than can be reached by a soldering iron, to be liquefiable at the same relatively low temperature with the aid of a solvent metal like molten solder? Summarize your findings in your notebook and post your conclusions and responses to the above points, evaluation will be based on timeliness & accuracy Quiz tomorrow. BTW, if I was already going to be rewiring a guitar anyway, I wouldn't hesitate to use pure silver wire in place of the copper ordinarily seen, provided the price differential was not beyond my tolerance for experimental costs. It certainly couldn't sound worse than copper. Just trying in a friendly way to give you a hard time where it is due Best Regards, Mike

4/26/2000 2:54 PM

MBSetzer

Mark L. Wrote:

>Silver is the *best* conductor of heat on the Planet, this molten >blob will certainly Stay hot and liquid longer than one is normally >used to.

An interesting thing about heat-conducting materials (hmm . . . wouldn't that be all materials?) is that the better the conduction, the more rapidly the same mass will cool off from the same temperature when exposed to the same environment.

In other words, as you observe the molten blob of silver-bearing solder stay hot & liquid longer than you are used to, it would NOT be due to superior heat conduction because of its silver content. Just the contrary, if you would heat ordinary 60/40 solder beyond its melting point to the same temperature that the higher-melting silver-bearing solder requires, it would take even longer to cool down to room temperature than the silver stuff.

Now lets dissolve another misconception.

>The temperature of easy flow solder(even Silver bearing solder) is >just not high enough to turn anything Silver into a liquid state.
>Even a thin micron-thick veneer like a plating. Soldering irons don't >get hot enough to turn Silver into liquid form. This takes a torch(or >equivalent) to do.

Since silver has long been known to dissolve in solder, it would naturally raise questions about any observations to the contrary. A common occurrence in the scientific laboratory is preliminary observation that needs further investigation, especially in those situations where the outcome may be unknown ;-)

Therefore the following experiment is suggested:

Of course you will need some pure silver (20 ga. wire would be about right), but who has that kind of stuff just lying around ;-)

A clipping from the wire about 1 or 2 millimeters long would be a good test piece.

Also you would need a different metal for a control sample, something known to be insoluble in solder, like stainless steel, in about the same size & shape as the silver. Probably a hardened sewing needle could be trimmed to size.

All proper laboratory safety equipment, especially eye protection when using clippers to trim metal stock, should be employed.

It might be nice to use a small ceramic crucible for the melted solder, but it could be better done on a level piece of wood (the amount of heat will not scorch it that bad), since the molten solder will have the consistency of ordinary liquid mercury and kind of hold the blob together, you don't want it to run downhill though.

For a heat source an ordinary soldering iron like they have at Radio Shack would be OK. Since you will be melting a blob of solder about 1 centimeter in diameter which is much bigger than most amplifier connections, use about a 50W iron instead of a 25W.

Start with the stainless piece and get a blob of solder hot nearby, use a little more than would stick to the tip of the iron when you lift it from the work area. Push the liquid solder to engulf the stainless test piece and seriously try to agitiate and heat the stainless together with the solder and get it to dissolve. Notice how even if the solder slightly wets the insoluble metal, you can always separate it from the liquid by dragging the blob and leaving the test piece behind.

Now repeat using the silver test piece, when it becomes difficult to leave any solid silver behind when moving the blob, record your impression of what has become of the silver at this point. If there is some suspicion that solid silver is suspended within the liquid solder without being dissolved, this could be confirmed or denied by passing the liquid through a stainless mesh with openings small enough to catch the original size test piece. Or you might use an intact sewing needle to probe around in the melted solder to see if any solid silver is still there. Don't hold the needle with your bare hands for this.

----- Review your impressions and comment on whether you think the temperature reached by the easy flow solder using an ordinary soldering iron was high enough to turn any silver into the liquid state.

----- Would you say that smaller amounts of silver, such as a thin micron-thick veneer-like plating would dissolve faster or slower than your experimental test piece?

----- Could you qualify the statement: *Soldering irons don't get hot enough to turn silver into liquid form*? Do you think it is surprising for pure metals with higher melting points than can be reached by a soldering iron, to be liquefiable at the same relatively low temperature with the aid of a solvent metal like molten solder?

Summarize your findings in your notebook and post your conclusions and responses to the above points, evaluation will be based on timeliness & accuracy ;-)

Quiz tomorrow.

BTW, if I was already going to be rewiring a guitar anyway, I wouldn't hesitate to use pure silver wire in place of the copper ordinarily seen, provided the price differential was not beyond my tolerance for experimental costs. It certainly couldn't sound *worse* than copper.

Just trying in a friendly way to give you a hard time where it is due ;-)

Best Regards,
Mike

4/27/2000 2:18 AM
Mark L.	Holy sht! Nah, I'm not in the mood for a test! Listen, instead of all that stuff, how about just trying* to make a teeny solid piece of Silver liquid, using only the soldering iron?....the heck with all that other stuff!(bg) Piece 'o cake. It ain't gonna happen. You'll fall asleep waiting for it to melt! Well, maybe I did word thing badly, but what i menat was since it takes such a higher temp to flow the silver-bearing stuff, the lower temp solder materials in the blend are fairly overheated. It just takes longer to cool enough to resolidify, and folks impatiently move too soon before it sets up right. Hey, I was (excuses excuses) dog tired when I wrote the post, and even double clutched it and couldn't get it out right!.......whatever, in general, the higher the temp, the longer it takes to cool. picky picky picky!(bg)egads! fwiw, silver is not all that expensive, provided one knows how to eliminate all the middlemen lingering abouts, with greedy little hands and itchy fingers... Thanks for the hard time, I owe ya one! seeya Mark L.

4/27/2000 2:18 AM

Mark L.

Holy sh*t!

Nah, I'm not in the mood for a test!

Listen, instead of all that stuff, how about just *trying* to make a teeny solid piece of Silver liquid, using only the soldering iron?....the heck with all that other stuff!(bg)

Piece 'o cake. It ain't gonna happen. You'll fall asleep waiting for it to melt!

Well, maybe I did word thing badly, but what i menat was since it takes such a higher temp to flow the silver-bearing stuff, the lower temp solder materials in the blend are fairly overheated. It just takes longer to cool enough to resolidify, and folks impatiently move too soon before it sets up right. Hey, I was (excuses excuses) dog tired when I wrote the post, and even double clutched it and couldn't get it out right!.......whatever, in general, the higher the temp, the longer it takes to cool.

picky picky picky!(bg)egads!

fwiw, silver is not all that expensive, provided one knows how to eliminate
*all* the middlemen lingering abouts, with greedy little hands and itchy
fingers...

Thanks for the hard time, I owe ya one!

seeya

Mark L.

4/26/2000 2:55 PM
Stephen Conner	Unfortunately it gets the Wooden Spoon in the 'value for money' category Steve C.

4/27/2000 2:12 PM
Mark L.	Sure, and that depends on who is trying to peddle the Silver, and how many middlemen have gotten into the food chain of the situation Since I make whatever I want in whatever shape/form I need, It's actually pretty inexpensive to play with... Mark L.

4/27/2000 4:04 PM

R.G.

quote:
"" Silver dissolves in liquid tin-lead solder like sugar dissolving in water..."

Sorry to butt in like this, but this statement simply is not true. The temperature of easy flow solder(even Silver bearing solder) is just not high enough to turn anything Silver into a liquid state.
Even a thin micron-thick veneer like a plating. Soldering irons don't get hot enough to turn Silver into liquid form. This takes a torch(or equivalent) to do."

Aye, my penchant for hyperbole gets me in hot water again.

Strictly speaking, you are right. A soldering iron will not melt a hunk of silver. What *will* happen is that a solder joint over a layer of silvered metal *will* leach the silver off the plated part.
Quoting from "Electronic Packaging and Interconnection Handbook" (McGraw-Hill, 1991),
"Leaching is recognized as an incident that can occur when noble metals, specifically silver and gold, are depleted from ... coatings and other compositions during soldering as a result of the ready solubility of silver and gold in molten tin.

The solubility of silver in molten tin is estimated to be up to 7% by weight at 250C, 10% by weight at 300C, and 16% by weight at 350C. ... a leached ... conductor composition may lose adhesion on the substrate and even be totally peeled off, while the solder may have undesirable intermetallic compounds"

This is why, as I said, SMD solder contains a bit of silver - the silver content helps prevent silver migration away from the silvered leads by pre-filling the solder with silver to slow leaching. The silver content in silver bearing solders varies. 2% was common on our solder wave machines in the production line when I looked last, but that could well have been cost saving at the price of upping the temp on the wave solder machines by several degrees. I don't recall off hand the phase diagrams for silver bearing solders, but 4% may well melt a little lower.

While we're butting (in the spirit of sharing, no offense intended, also), silver is, alas, not the bes conductor of heat on the planet. That distinction goes to diamonds, which are, paradoxically, insulators. The thermal conductivity of diamond is about *five times* the thermal conductivity of silver or copper. Silver is the best *metallic* heat conductor, beating copper by a modest percentage, and then by a group led by aluminum as I remember.

quote:
" Some folks move too fast, and the semi-molten blob tries to solidify while it is cooling and reforming into a solid. This result looks like a 'crumbly' solder joint, and is in fact prone to breaking from vibrations."

The rate at which a blob of solder cools depends on a lot of things - first and foremost the specific heat of the material and the thermal conductivity and size of the substrate the blob is on compared to the size of the blob, the thermal emissivity of the blob, the surrounding air currents; that covers the actual heat transfer out.

The *apparent* cooling rate depends on the specific composition of the alloy, and can be predicted by eyeballing a phase diagram, which is three dimensional for three way tin/lead/silver alloys. The fastest *apparent* cooling rate is for any eutectic alloy.

As an example, eutectic tin/lead, about 62/38 if my memory serves, has *no* musy solidification region. If the alloy is of the perfect composition it goes directly from liquid to solid, with no apparent mushy phase at all. The transition of eutectic solder to solid is a wonder to behold - liquid, then bang! solid! The rapid transition is a really valuable thing, as it's much harder to make cold, crumbly joints when the transition is so fast.

Also, eutectic alloys will have the lowest melting point for the constituent metals. Eutectic tin/lead melts at the lowest temperature of any alloy of the two. I don't know if tin/lead/silver has a eutectic point, as I haven't seen the phase diagram. In fact, I don't know if any of the several concoctions of lead free solders, which include pure tin, tin-antimony, tin-antimony, silver, and probably others I haven't seen, have eutectic alloys or not.

quote:
"Fwiw, Radio Shack sells a decent Lead-FREE high Silver content solder for a pretty low cost. Lead is pretty much a NON-conductor..."

Well, maybe if compared to silver. Lead, or more importantly, tin-lead, is a doggone fine conductor compared to any of the common things we consider insulators. It does pretty well in car batteries, where the internal plates are pure lead as well. I don't have the numbers in front of me, but I suspect that silver content under 5% hardly changes the bulk conductivity of tin-lead solder at all. It does a fine job of preventing leaching, though.

R.G.

4/27/2000 7:05 PM
jason	As an example, eutectic tin/lead, about 62/38 if my memory serves, has no* musy solidification region.* Eutectic solder is 63/37. Standard 60/40 solder has about a 14 degree range where it is in a semi solid/semi liquid plastic state. jason

Page 2 of 3